Classify the shutdown before it begins
Distinguish a short interruption, an extended shutdown and storage of removed or new elements. Time matters, but so do temperature, water quality and the ability to keep the circuit filled. One manufacturer’s categories and intervals should not automatically be applied to another membrane.
Identify responsible staff and resources available during the shutdown. A procedure requiring periodic checks cannot be implemented if nobody has access to the plant. Record models, element quantity, initial condition and expected restart date to select applicable instructions instead of relying on a generic chemical recipe.
Prepare the circuit for its actual condition
A fouled plant needs assessment of cleaning before preservation; adding preservative does not remove deposits. Check whether relevant sections can be drained, filled and vented, and identify regions isolated from the preservation liquid. Verify compatibility of membranes, seals and auxiliary equipment.
Hydranautics documents distinguish storage of installed elements from start-up and flushing procedures. Choose the preservative and its conditions using the applicable instructions and product information. A biocide effective during a cleaning operation should not automatically be assumed suitable for months of storage.
| Timing | Decision | Record |
|---|---|---|
| Before shutdown | Cleaning and applicable procedure | Baseline and models |
| During shutdown | Maintain preservation condition | Inspections and solution checks |
| Restart | Flush and accept quality | Residuals and performance |
Define checks throughout the idle period
Prepare a record for temperature, level or tightness, solution condition and intervention dates. The method should detect leakage or loss of the required preservation condition at different locations, particularly where the circuit may admit air. Ensure sampling itself does not compromise the preserved system.
As a planning example, a six-week shutdown exceeds the thirty-day boundary Hydranautics uses for its long-term category. That prompts consultation of its specific procedure; it does not establish a universal chemical concentration or replacement interval applicable to membranes from other manufacturers.
Include return to service in the scope
Allow water and time for flushing, a discharge route and measurement of the relevant residual. Conductivity alone may not identify every preservative. Water suitability depends on intended use and applicable controls, so initial output must be managed according to the selected procedure.
After stabilisation, compare quality, normalised flow and pressure drop with the pre-shutdown condition. Document incidents and retain traceability of removed elements. For sealed spares, check packaging, storage temperature and supplier instructions rather than treating the purchase date as proof of an assured remaining service life.
Common questions
Is leaving the membranes filled with water enough?
That cannot be assumed for every duration and temperature. The applicable instruction must define preparation, monitoring and action for the planned interval.
Can new and used elements be stored identically?
Not necessarily. Factory-sealed elements and previously operated elements have different histories and conditions. Check the instructions for each case.